| REQUIREMENTS The invention is a continuous olive oil production which make, use of a crusher (2)to crush the olives , a malaxator set (3)to knead the olive paste, a twin-piston hydraulic pump(5) to pump the olive paste to the screw press, blending and conveyor arms(6) and vibration motor(7) to prevent the pump from sucking the air in, the screw press for cold pressing (8)that runs under pump pressure, a malaxator set (10)that can knead the semi-oily pomace with the desired amount of hot water, a twin piston hydraulic pump (12), and a screw press(13) that operates under the pressure of the latter in order to produces two different types and qualities of olive oil products: extra-virgin and virgin olive. |
CONTINUOUS EXTRA-VIRGIN AND VIRGIN OLIVE OIL PRODUCTION PROCESS
This method concerns the continuous virgin and extra-virgin olive oil production process. There are two types of olive oil production; one is discontinuous process using classical disc presses, and second production type is the continuous process by centrifuging via decanters.
In order to produce olive oil with the classical system where traditional presses are used, first, the olives are crushed and kneaded in millstone mills. The kneaded paste is then bagged and stashed in stockpiles. The oily juice that comes out of the first press is settled in settlement tanks or troughs, so that it separates from vegetative water and accumulates on the surface. Oil that accumulates on the surface is scraped and collected as extra virgin olive oil.
For the second press, the disks are prepared then hot water is sprayed onto semi-oily pomace that is left inside the bags. The bags are pressed for a second time. The juice that comes out from this second press yields virgin olive oil. The classical system is both a labor- intensive process and demands the use of classical equipment that lacks of required hygiene level. Hence it is less preferred than the continuous decanter type production which is more hygienic and less costly.
Production using decanters yields only a single type of olive oil, moreover producers need to add water or vegetative water to the olive paste to make it softer and more fluid for smoother decanter operation.
Olive oil that is produced by using decanters fails to give the same taste and aroma of the product that is produced using the classical method. Yet, it is still more hygienic and less labor-intensive.
In recent years, producers are inclined to leave more oil in the pomace in order to increase the quality of the oil. However, this approach causes economic losses.
This method brings together the advantages of the classical disk press and the continuous decanter systems.
Olives that are washed and separated from their leaves are pressed in pressurized screw presses without adding any water and vegetative water; just like the classical system. This yields extra-virgin olive oil. Olive paste is treated with hot water then kneaded again and get ready for the second press. Then it is hot-pressed like in the classical method, with the pressurized screw press or decanter to yield virgin olive oil.
The screw presses are operated under pressure since olive paste is more fluid than oily seeds. To achieve obtaining virgin olive oil, the press requires a pressure around 80-100 kg/cm 2 at the exit of the screw press.
Process control is ensured by adjusting both the screw press exit nuzzles, and the twin- piston pump pressure, A detailed description of this method is as follows:
Process is run by the operation of the combined machinery shown in Drawing 1. Machines that are numbered in the drawings are as follows:
Drawing 1: Continuous virgin and extra-virgin olive oil process:
1- Crushing bunker
2- Crusher
3- Malaxator set
4- Screw conveyor
5- Twin-piston hydraulic pump
6- Blender and conveyor arms
7- Vibration motor
8- Screw press for cold press
9- Juice outflow pipe
10- Hot water blender
11- Screw conveyor
12- Twin-piston hydraulic pump
13- Screw press for hot press
14- Mono-pump
15- Decanter
Olives that are washed and de-leaved are loaded to the crushing bunker (1) where they are crushed until they reach to the required size depending on the particular type of olive. Crushed olives are kneaded in the malaxator set (3) for about an hour. Kneading is best done at ambient temperatures however in some special cases the paste might require warming-up; in this case the blender must be a water-jacket type. Olive paste that is kneaded is conveyed, via the conveyor screw (4) to the twin-piston hydraulic pump bunker (5). The twin-piston pump or the concrete pump, as it is widely known, has to be equipped with conveyor arms (6) inside the bunker and with vibrator motor (7) outside so that the pump does not suck any air in. Depending on the fluidity of the olive paste, these two contraptions are either separately or simultaneously operated and the air-free olive paste is conveyed to the pressurized screw press to be cold-pressed. The olive paste is pressed under pressure in the screw press (8). A pressure of 80-100 kg/cm 2 at the screw press exit nuzzle would be sufficient. This pressure is partly generated by the pump and partly by the screw press. The fluidity of the olive paste requires this pressure be attained at the inlet of the screw press. Pressure of the pump increases towards the nuzzle depending on the screw pitch, speed and the load amount, and the juice that oozes from small holes over the equipment body accumulates in the drain (9). Semi- oily pomace is obtained from the outflow nuzzle. Setting the pump pressure and the cross- section of the outflow nuzzle controls the process. Pre-filtering separates olive particles from the juice. Then, the oily vegetative water is separated either in settlement tanks or in the centrifuge. Product obtained is extra-virgin olive oil.
Production of extra-virgin olive oil requires that oil is separated from the olive paste in two steps. Traces of virgin oil (that is obtained during the second press) in the extra-virgin content deteriorate the quality of the product (as in the process with decanters). As this method allows pre-setting the amount of oil from the first and the second presses through the adjustment of pressure and nuzzles, the level of desired product quality is easily achieved.
Following the outflow of the semi-oily olive paste (pomace) from the screw press for cold pressing (8) it is conveyed to the hot-water jacket blender set (10) where it is re-kneaded by adding required amounts of hot water. (This type of kneading is not possible in the classical method). The paste is conveyed through the screw conveyor (11) to the twin-piston pump bunker (12) and it is pump-pressed in the screw press for hot pressing (13). Oily juice obtained in this way yields virgin olive oil after the centrifuge.
The pomace that is left after the extraction of the virgin oil from the olive paste via cold press is kneaded with the addition of water and it is sent to the decanter(15) by a mono- pump(14) for decomposition. As the quality of the oil product at this stage is not important the manufacturer can choose between a decanter or a screw press.